Feasibility, Acceptability, and Preliminary Target Engagement of a Healthy Physical Activity Promotion Intervention for Bulimia Nervosa: Development and Evaluation via Case Series Design.

Bulimia nervosa (BN) is characterized by a pattern of binge eating and compensatory behaviors as well as an overemphasis on body weight and shape in self-evaluation. Although cognitive behavioral therapy (CBT) is efficacious, recent reviews suggest that only 30% of patients reach abstinence at posttreatment. One potential reason for these poor outcomes is that CBT fails to adequately reduce elevated negative affect (NA) and shape and weight concern, which have been shown to be correlated with poorer treatment outcomes in BN. Therefore, novel treatment components that focus on improving NA and shape and weight concern are needed in order to enhance outcomes. Promoting physical activity (PA) is a promising avenue through which to reduce NA and improve body image in healthy individuals, other clinical populations (e.g., individuals with depression or anxiety), and individuals with eating disorders. While prescribing PA for individuals with BN has been controversial (due to concerns that exercise maybe be used to compensate for binge episodes or become driven or compulsive), this approach may have many benefits, including promoting healthy lifetime exercise habits that reduce likelihood of relapse through the improvement of emotion regulation skills and weight regulation. Given the promise of PA for targeting key maintenance factors of BN, we developed a 12-session healthy PA promotion intervention for BN and tested initial feasibility, acceptability, and preliminary target engagement in an iterative case series design (n = 3). The treatment provided cognitive-behavioral skills designed to identify, practice, and achieve behavioral goals while asking patients to engage in up to 150 minutes of moderate-to-vigorous PA per week, which was preplanned during each session with the client's therapist. Results suggested that the healthy PA promotion intervention was both feasible and acceptable to deliver. In addition, the intervention resulted in a clinically significant decrease in BN symptom frequency in each participant. Further, participants showed clinically significant decreases in NA and shape and weight concern. The current study demonstrates that healthy PA interventions can have beneficial effects on BN symptoms, NA, and shape and weight concern. However, due to the small sample size, conclusions must be treated with caution. Future research should investigate additional approaches for promoting healthy PA and include a larger sample in order to further test initial efficacy of this treatment approach.